Ground rods within 6 feet

[zcanyonboltz]

I'm doing two separate service changes on a duplex. There is very little space in the back of the units where the panels are going. I was able to separate 1 unit's ground rods 6 feet apart. When I do the ground rods for the other unit I can get them six feet apart.... but the question is I may not be able to have 6 feet between each separate system...any thoughts on this. Thanks

 

[texie]

You only need one grounding electrode system for both. Even if you had one for each they would have to be bonded together anyways.

 

[zcanyonboltz]

Thanks

 

[infinity]

The rods that make up two separate GES's do not require separation. SInce this a duplex is it being treated as two separate structures?

 

[zcanyonboltz]

Im not sure...it has on drop and two seperate meters and panels.

 

[James L]

When I was wiring some duplexes a few years ago, each main breaker had to be grounded separately. 4 ground rods total.

I put 2 ground rods on the left about a foot from each other. Then about 8 feet away on the right, another 2 ground rods a foot from each other.

#6 from each panel going to the left and
#6 going from each panel to the right

 

[Hv&Lv]

connect one panel GEC to rods, continue through second rod to second panel.

 

[augie47]

Here it would be done as above (post @#7)

 

[zcanyonboltz]

Thanks for replies and drawing. If l use 2 ground rods only the GEC must be continuous. One panel is already done so it looks like I'm doing what was posted in post 6.

 

[zcanyonboltz]

Now lm starting think about cold water ground...l already ran a #4 for first unit we already did...was l supposed to run one continous for both or can l can l have two separate ones?

 

[James L]

How many amps is each panel?

 

[petersonra]

Thanks for replies and drawing. If l use 2 ground rods only the GEC must be continuous. One panel is already done so it looks like I'm doing what was posted in post 6.

I don't see that it has to be continuous. You can install a bonding jumper between the two ground rods.

 

[zcanyonboltz]

I thought GEC must be continuous.... both 200A mains. One feeds a sub inside house

 

[GoldDigger]

If there is a high enough rated firewall between the units, it is more likely that it would be possible to treat it as two separate buildings.
But that is less likely to fly in light of specific NEC sections for 2 and 3 family dwellings.

 

[zcanyonboltz]

If there is a high enough rated firewall between the units, it is more likely that it would be possible to treat it as two separate buildings.
But that is less likely to fly in light of specific NEC sections for 2 and 3 family dwellings.

Are you saying one GEC system or two separate ones is less likey to fly?

 

[tom baker]

In WA if the rods are closer than 6 ft for two different services, they are required to be bonded together (per state electrical code), which is the intent of the NEC. Closer than 6 ft the shells of the earth overlap and its only one rod.
And the GEC is only required to be continuous to the first electrode, from there its a bonding jumper to the other rod, or 3 clamps and 2 wires.
Some inspectors want 2 clamps and one wire, but thats not what the NEC says

 

[kwired]

Since this is a multioccupancy situation and you appear to have both service disconnects in close proximity to one another I think you have more options than usual. You can have a service to each occupancy, or since they are in close proximity you can have one service with two disconnecting means. Use the rules that apply to either and do what works best for your application.

As far as water pipe - is it qualifying electrode? Is there just one supply pipe for both units or does each have a separate line to it?

If not a qualifying water pipe electrode then all you need is a bond to any interior metal piping system (if this applies) in each unit.